Aspects of atmospheric circulation: the late Pleistocene (0-950,000 yr) record of eolian deposition in the pacific ocean

Abstract

The eolian component of pelagic sediments provides a proxy record of atmospheric circulation intensity and of dust transport. Examination of those records indicates that the atmosphere responds to orbital forcing but that during the past 875,000 years the, variability in atmospheric circulation is at much shorter periods than the 100,000-year variation in ice volume. The mid-Brunhes climatic event is well characterized in the eolian grain-size records and in records of sea-surface phenomena; it is not seen in proxy indicators of either deep-water or ice-volume variability. The increase in the amplitude of paeloclimatic variability that denotes the early/late Pleistocene transition occurs suddenly about 875,000 years ago in the eolian grain-size record, which is about 20,000 to 25,000 years earlier than the transition in the deep sea CaCO3-dissolution record or in the [delta]18O proxy record of ice volume.